Climate Bulletin For Sri Lanka (21 May 2021)

 

Highlights          

                   

  •   Showers of 145 mm expected in Western, Southern and Sabaragamuwa during 21st May – 1st June.

  •   Last week was wetter than normal in most of SL.  Thunder showers in Western province with a maximum of  336 mm in Kalutara on 13th May.

•  From 11th  - 17th May: up to 10 km/h from the West and South wind were experienced. Cyclone Takutae travelled along the western part of the Kerala, Maharashtra and Gurajat coasts and there were long-range effects even this week.   

•  Sea surface temperature was observed around 0.5℃ above average around the island.

•  The SST forecast indicates that the La Niña event has transitioned to ENSO-neutral. 

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Monitoring

Rainfall
Total Rainfall for the Past Week: 

The RFE 2.0 tool shows Cumulative rainfall by Districts:

• 150 – 200 mm  - Moneragala
• 100 – 150 mm - Polonnaruwa, Puttalam, Kurunegala, Batticaloa, Ampara, Kandy, Nuwara Eliya, Badulla, Gamapaha, Colombo, Kalutara, Galle, Matara, Hambantota, Kegalle, Ratnapura
• 75 – 100 mm - Anuradhapura, Trincomalee, Matale
• 50 – 75 mm - Kilinochchi, Mannar, Mullaitivu, Vavuniya
• 25 – 50 mm - Jaffna
  

Weekly rainfall Anomalies by Districts

Rainfall Excess

• 100 – 200 mm - Polonnaruwa, Hambantota, Moneragala, Badulla, Ampara, Batticaloa
• 50 – 100 mm - Mannar, Mullaitivu, Vavuniya, Anuradhapura, Puttalam, Kurunegala, Trincomalee, Matale, Kandy, Nuwara Eliya, Kegalle, Ratnapura, Gampaha, Colombo, Kalutara, Galle, Matara
• 25 – 50 mm - Jaffna, Kilinochchi

Monthly Monitoring: 

Dekadal Rainfall by Districts:

21^st – 30^th April:

• 16 mm - Badulla, Moneragala, Ampara
• 14 mm - Kegalle
• 12 mm - Kalutara, Galle, Matara, Ratnaputa, Kandy, Vavuniya, Mannar
• 10 mm - Gampaha, Colombo, Hambantota, Nuwara Eliya
• 8 mm - Mullaitivu, Batticaloa, Kurunegala
• 6 mm - Anuradhapura, Puttalam, Matale
• 4 mm  - Polonnaruwa, Trincomalee
• 2 mm - Jaffna, Kilinochchi

1^st – 10^th May:

• 16 mm - Gampaha, Colombo, Kalutara, Galle, Matara, Hambantota, Kegalle, Ratnapura, Nuwara Eliya, Kandy, Matale, Badulla, Moneragala, Anuradhapura, Mannar, Vavuniya, Mullaitivu, Puttalam, Kurunegala
• 14 mm - Ampara, Kilinochchi
• 12 mm - Polonnaruwa
• 6 mm- Batticaloa, Trincomalee
• 4 mm  - Jaffna
  

Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 21^st – 25^th May: 

Total rainfall by Provinces: 

• 145 mm - Western, Southern, Sabaragamuwa
• 125 mm - Central
• 95 mm - North Western
• 85 mm - Uva
• 75 mm - North Central
• 65 mm - Northern, Eastern

From 26^th May – 1^st June: 

Total rainfall by Provinces:

• 145 mm - Southern, Sabaragamuwa
• 125 mm - Western
• 105 mm - North Western, Central
• 95 mm  - Uva
• 55 mm  - North Central
• 45 mm  - Northern, Eastern

MJO based OLR predictions:

For the next 15 days: 

 MJO shall significantly enhance the rainfall during 18^th–22^nd May, Neutral during 23^rd– 27^th May and severely suppressed rainfall during 28^th May – 1^st June.

Ocean State (Text Courtesy IRI)

Pacific sea state: May 12, 2021 

Equatorial SSTs were mostly below average from the east to the Middle West Pacific Ocean in mid May and most key atmospheric variables were either ENSO –Neutral or consistent with continued La Niña conditions. A large majority of the model forecasts predict SSTs to be cooler than the threshold of La Niña SST conditions through the winter, dissipating during spring.

Indian Ocean State

Sea surface temperature was observed around 0.5℃ above average around the island.